body {
  margin: 5ex 10ex;
  max-width: 80ex;
  line-height: 1.5;
  font-family: sans-serif;
}
h1, h2, h3 {
  font-weight: normal;
}
pre, code {
  font-family: x, monospace;
}
pre {
  padding: 1ex;
  background: #eee;
  border: solid 1px #ddd;
  min-width: 0;
  font-size: 90%;
}
code {
  color: #007;
}
div.chapter {
  margin-top: 4em;
  border-top: solid 2px black;
}
p {
  margin-top: 0;
}
